An ionic compound has a unit cell consisting of A ions at the corners of a cube and B ions on the centers of the faces of the cube. The empirical formula for this compound would be : 

1. AB 

2. A₂B

3. AB₃

4. A₃B

The formula of nickel oxide with metal deficiency defect in its crystal is $N{i}_{0.98}O$. The crystal contains ${\mathrm{Ni}}^{2+} \mathrm{and} {\mathrm{Ni}}^{3+}$ ions. The fraction of nickel existing as $N{i}^{2+}$ ions in the crystal is-

1. 0.96

2. 0.04

3. 0.50

4. 0.31

The edge length of fcc unit cell of NaCl is 508 pm.
If the radius of cation is 110 pm then radius of the anion is : 

1. 244 pm

2. 144 pm

3. 288 pm

4. 398 pm

An element occurring in the bcc structure has $12.08\times {10}^{23}$ unit cells. The total number of atoms of the element in these cells will be:

1. $24.16\times {10}^{23}$

2. $36.18\times {10}^{23}$

3. $6.04\times {10}^{23}$

4. $12.08\times {10}^{23}$

A compound that shows Schottky as well as Frenkel defect among the following is -

1. ZnS               

2. AgBr             

3. NaCl                 

4. AgCl

If an element (at. Wt. = 50) crystallises in fcc lattice, with a = 0.50 nm, then the density of unit cell if it contains 0.25 % Schottky defect is -

(Use $N_A=6\times {10}^{23}$) 

1. 2.0 g/cc

2. 2.66 g/cc

3. 3.06 g/cc

4. None of the above.

In the spinel structrue, oxides ions are cubical-closest packed whereas 1/8th of tetrahedral voids are occupied by ${\mathrm{A}}^{2+}$ cation and 1/2 of octahedral voids are occupied by ${\mathrm{B}}^{3+}$ cations. The general formula of the compound having spinel structure is :

1. ${\mathrm{A}}_2{\mathrm{B}}_2{\mathrm{O}}_4$

2. ${\mathrm{AB}}_2{\mathrm{O}}_4$

3. ${\mathrm{A}}_2{\mathrm{B}}_4{\mathrm{O}}_2$

4. ${\mathrm{A}}_4{\mathrm{B}}_2{\mathrm{O}}_2$

An element has a body-centered cubic (BCC) structure with a cell edge of 288 pm. The atomic radius is:

1. $\frac{\sqrt{2}}{4}\times 288$ pm

2. $\frac{4}{\sqrt{3}}\times 288$ pm

3. $\frac{4}{\sqrt{2}}\times 288$ pm

4. $\frac{\sqrt{3}}{4}\times 288$ pm

Select the correct option based on statements below:

The crystal with a metal deficiency defect is - 

1. NaCl 

2. FeO

3. ZnO 

4. KCl